"There's always enormous interest, obsession if you like and what Kate wears," she said. "Every single time people talk about what she wears it gets sent around the world and everyone's trying to copy her look. That of course is going to be a huge theme on the tour."

Kate wore a printed cotton dress by designer Tory Burch for a group play date Tuesday with parents and children from New Zealand.

Within hours, the dress, which retails for $450, had sold out on Net-a-Porter.com and on the designer's U.K. website.

"Women around the world look to her to know what to wear so as soon as Kate wears something, it's immediately sold out," said London-born entrepreneur Rosie Pope, the creative force behind Rosie Pope Maternity.

Kate Sunday sported a red Catherine Walker coat dress with a pillbox hat by Gina Foster. The look reminded many of Prince William's mother, Princess Diana, during her own tour to New Zealand in the 1980s with a then-baby William.

Duchess Kate, 32, isn't the only one receiving accolades for her style. Her son, Prince George, is also winning praise for his fashion picks. The traditional rompers that he has sported this week are reminiscent of those worn by his father, William, when he was a baby on his own tour of New Zealand 31 years ago this month.

On Tuesday, George, whose broad smiles display his first teeth, was gifted Tuesday with a new friend: a blue teddy bear from the Royal New Zealand Plunket Society, which provides health care to young children.